Decentralised home ventilation with the Maico Push/Pull system
In order to meet the requirements of the Energy Saving Ordinance (EnEV), modern residential buildings must have effective thermal insulation and high impermeability. This prevents the expensive heat generated from escaping via the building structure and leaks. This minimizes the primary energy required to generate a comfortable room temperature. This has a number of significant advantages, including lower energy costs for the home user and a reduction in the CO2 climate killer produced during energy generation. But unfortunately there are also disadvantages.
The problem: lack of air exchange
For a healthy and comfortable room climate, a constant exchange of room air is also necessary. In this way, “used” air and the moisture it contains are removed to the outside and replaced by fresh air. If the air in a room used by people is not continuously exchanged, the oxygen content decreases, while the proportion of exhaled CO2 and the moisture released through the skin increases. In addition, there are outgassings from furniture, floor coverings and other furnishings. The result is an unhealthy gas mixture that can cause discomfort in the short term and considerable health damage in the long term. In addition, the air humidity is deposited in poorly accessible places on the walls and can promote the unnoticed development of mold.
Controlled central ventilation and its disadvantages
In the buildings that were common in the past, the leaking walls, windows and doors caused a kind of natural exchange of air that is no longer possible today. Even the infamous window ventilation is only an inadequate replacement, especially since it is often carried out incorrectly. The only real remedy is to use controlled domestic ventilation (KWL), which is particularly used for low-energy and passive houses and often also has heat recovery from the exhaust air. With the aid of its sensors, the system ensures a ventilation and exhaust that meets demand, guarantees a minimum air turnover and uses the heat of the exhaust air to control the temperature of the supply air. The disadvantage of such a system is the relatively high space requirement for the central unit with fan and heat exchanger and the ventilation ducts which direct the fresh air to each room and transport the exhaust air from each room to the central heat exchanger. The aesthetic aspect also plays a role. Not everyone likes visible air ducts in their living rooms, even if they are very flat and inconspicuously coloured.
The modern solution: decentralised home ventilation
Based on the aforementioned disadvantages, central controlled ventilation is almost exclusively suitable for new buildings where the required space is planned from the outset. Retrofitting of existing buildings is rarely possible. This situation led to the development of the decentralised ventilation system for residential areas where each room has its own ventilation unit, in which heat recovery from the exhaust air is even integrated. Fortunately, the days of clumsy individual room ventilation are over. With these modern solutions, the complete technology with fan and heat exchanger is concealed in the wall sleeve, which connects the outside cover with the inside cover and serves as the air duct.
Maico PushPull 60
One representative of these modern individual room ventilations is the PushPull 60 of the well-known fan manufacturer Maico. The fact that this decentralised ventilation system is so compact and still has heat recovery is made possible by an ingenious trick. It is certainly clear that the small dimensions mean that supply and exhaust air cannot be routed through the unit at the same time as passing through a classic cross-flow heat exchanger. The PP 60 works alternately for 70 seconds each in supply and return air operation. During exhaust air operation, around 80 % of the heat energy of the exhaust air flow is stored in the innovative ceramic heat exchanger and is transferred to the supply air flow during supply air operation, which is also cleaned by the integrated filters. In order to guarantee simultaneous operation of the supply air and extract air branches, as is the case with a central ventilation system, these individual room ventilators are always operated in pairs. This means that if unit 1 is in supply air mode, unit 2 operates in extract air mode. After 70 seconds, the unit changes automatically.
The Maico PushPull 60 is operated via an external control to which 2, 4 or a maximum of 6 units can be connected. One unit can deliver up to 55 m3/h of air. Depending on the size of the rooms, it may not be necessary to install a matching pair in the same room. Conversely, in very large rooms, several pairs can also provide the necessary air delivery capacity. The ventilation units can be operated via the external room air control in 5 ventilation stages. In addition to the automatic ventilation with heat recovery and preselected ventilation stage, there are the operating modes transverse ventilation and dehumidification. With cross ventilation, one unit with preselected ventilation stage works permanently in supply air mode, the other in extract air mode. Heat recovery is not possible here. This operating mode is suitable if, for example, intensive ventilation is required to remove unpleasant odours. In dehumidification mode, optimum dehumidification of the relevant rooms is carried out with the aid of the optionally available humidity sensor.
Wide range of applications for modern decentralised domestic ventilation
The compact decentralised ventilation systems PushPull 60 from Maico are suitable for retrofitting due to their small dimensions, the elimination of ventilation ducts and the low installation costs. But they are also an interesting and cost-effective alternative for new buildings, which can even be used in rented flats, old people’s and nursing homes or other facilities with a similar usage profile. They therefore represent an efficient solution for demand-oriented ventilation not only for home builders and owners, but also for property developers and building administrators, and for the prevention of mould infestation in residential units.